Field of the Invention
The present invention relates to a projection image generating device, method and program that generate a projection image from volume data representing a three-dimensional region including a hollow organ.
Description of the Related Art
In the medical field, volume data (three-dimensional image data) obtained by photographing a patient is converted into an image suitable for observation and displayed. In particular, a virtual endoscopic image is widely used for observation of a hollow organ such as a large intestine or a bronchus.
However, in the virtual endoscopic image, there may be a portion in which a visual line is blocked by a front wall or the like and does not appear on the image. For example, when there are a large number of folds on an inner wall of the large intestine and the view point exists on a side surface of any of the folds, there is a problem in that a lesion (e.g., polyp) on a back surface of the fold does not appear on the image and cannot be observed.
On the other hand, a scheme in which a view point is placed inside a hollow organ and the hollow organ is drawn as a mesh or a translucent organ such that an image in which a back wall blocked by a front wall of the hollow organ and not visible has been drawn is displayed to be superimposed on an image in which the front wall of the hollow organ has been drawn has been proposed in JP1998-234663A (JP-H10-234663A). A scheme in which a projection image generated by placing a view point outside a hollow organ is displayed side by side with a virtual endoscopic image generated by placing the view point inside the hollow organ, or switched to the virtual endoscopic image and displayed such that the hollow organ can be observed from various view points has been proposed in JP2007-537771A.